How to update a file in yii2?

Question

Yii

I want to do something like a blog. Generated the usual CRUD. I screwed up the ability to add an image to the post, but the problem arose in Update. I can't overwrite the image
. The post id and photo are saved in the database (for example: link/post-id.jpg)
When updating, I just want to change the image itself in the folder so that it is overwritten. So that the old one is deleted and the new one is preserved
Please help
Below is the function of updating the post, in which I wanted to first delete and overwrite again, but it didn’t work out ...

public function actionUpdate($id)
    {
        $model = $this->findModel($id);

        if ($model->load(Yii::$app->request->post()) && $model->save()) {
            $file = $this->findModel($id)->photo; // 'images/'.$file (physical path)

            if (file_exists($file)) {
                unlink($this->findModel($id)->photo);
                $this->findModel($id)->delete();

                return $this->redirect(['view', 'id' => $model->post_id]);
            } else {
                return $this->render('update', [ 'model' => $model, ]);
            }
        }